A substance being studied in the treatment of breast cancer that has come back. It binds to receptors for a protein called vascular endothelial growth factor (VEGF). This keeps VEGF from binding to the receptors and may stop the growth of new blood vessels that tumors need to grow. It is a type of antiangiogenesis agent and a type of monoclonal antibody. Also called anti-VEGFR-2 fully human monoclonal antibody IMC-1121B and IMC-1121B.